The knee joint includes the interface between the distal end of the femur and the proximal end of the tibia. In a properly-functioning knee joint, medial and lateral condyles of the femur pivot smoothly along menisci attached to respective medial and lateral condyles of the tibia. In certain knees, such as diseased arthritic knees, cartilage may have eroded, causing the space between the femur and the tibia to collapse and leading to bone-on-bone contact. When this happens, the natural bones and cartilage that form the joint may be unable to properly articulate, which can lead to joint pain and/or interfere with normal use of the joint.
In some situations, surgery is required to correct the alignment between the tibia and femur and restore normal use of the joint. Depending upon the severity of the damage, the surgery may involve partially or completely replacing the joint with prosthetic components. During such knee replacement procedures, a surgeon resects damaged portions of the bone and cartilage, while attempting to leave healthy tissue intact. The surgeon then fits the healthy tissue with artificial prosthetic components designed to replicate the resected tissue and restore proper knee joint operation.
The orientation of these prosthetic components on the tibia and/or femur may impact the alignment between the tibia and the femur and thus affect how the joint articulates. Improperly oriented prosthetic components may fail to restore proper knee joint operation and/or may cause premature component failure or deterioration, among other problems. Accordingly, proper orientation of these components is critical, and a surgeon may spend a great deal of time and effort determining the proper orientations of the prosthetic components before fitting them to the joint. However, even with the surgeon's experience, making such a determination manually may not result in an optimal, or even acceptable, location and orientation of the prosthetic components.